﻿#if NETFRAMEWORK
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

namespace System.Collections.Generic;

/// <summary>
/// Provides a readonly abstraction of a set.
/// </summary>
/// <typeparam name="T">The type of elements in the set.</typeparam>
internal interface IReadOnlySet<T> : IReadOnlyCollection<T>
{
	/// <summary>
	/// Determines if the set contains a specific item
	/// </summary>
	/// <param name="item">The item to check if the set contains.</param>
	/// <returns><see langword="true" /> if found; otherwise <see langword="false" />.</returns>
	bool Contains(T item);
	/// <summary>
	/// Determines whether the current set is a proper (strict) subset of a specified collection.
	/// </summary>
	/// <param name="other">The collection to compare to the current set.</param>
	/// <returns><see langword="true" /> if the current set is a proper subset of other; otherwise <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool IsProperSubsetOf(IEnumerable<T> other);
	/// <summary>
	/// Determines whether the current set is a proper (strict) superset of a specified collection.
	/// </summary>
	/// <param name="other">The collection to compare to the current set.</param>
	/// <returns><see langword="true" /> if the collection is a proper superset of other; otherwise <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool IsProperSupersetOf(IEnumerable<T> other);
	/// <summary>
	/// Determine whether the current set is a subset of a specified collection.
	/// </summary>
	/// <param name="other">The collection to compare to the current set.</param>
	/// <returns><see langword="true" /> if the current set is a subset of other; otherwise <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool IsSubsetOf(IEnumerable<T> other);
	/// <summary>
	/// Determine whether the current set is a super set of a specified collection.
	/// </summary>
	/// <param name="other">The collection to compare to the current set</param>
	/// <returns><see langword="true" /> if the current set is a subset of other; otherwise <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool IsSupersetOf(IEnumerable<T> other);
	/// <summary>
	/// Determines whether the current set overlaps with the specified collection.
	/// </summary>
	/// <param name="other">The collection to compare to the current set.</param>
	/// <returns><see langword="true" /> if the current set and other share at least one common element; otherwise, <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool Overlaps(IEnumerable<T> other);
	/// <summary>
	/// Determines whether the current set and the specified collection contain the same elements.
	/// </summary>
	/// <param name="other">The collection to compare to the current set.</param>
	/// <returns><see langword="true" /> if the current set is equal to other; otherwise, <see langword="false" />.</returns>
	/// <exception cref="ArgumentNullException">other is <see langword="null" />.</exception>
	bool SetEquals(IEnumerable<T> other);
}
#endif
